Galileo sat-nav rides into orbit

21 October 2011 Last updated at 06:31 ET By Jonathan Amos Science correspondent, BBC News <!-- Embedding the video player --> <!-- This is the embedded player component -->

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The Soyuz rocket carrying the first two satellites lifts off from the base in French Guiana

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Europe's first satellite-navigation spacecraft are heading into orbit.

The two Galileo satellites were launched by a Russian Soyuz rocket from its new base in French Guiana at 07:30 local time (10:30 GMT; 11:30 BST).

The European Commission (EC) is investing billions of euros in its own version of the American GPS system.

It expects Galileo to bring significant returns to EU nations in the form of new businesses that can exploit precise space-borne timing and location data.

The Soyuz mission is a long one - it will be several hours before confirmation is received that the satellite pair have been put in their correct orbit 23,000km above the Earth.

The spacecraft are pathfinders for the Galileo system as a whole.

Together with another pair of satellites to be lofted next year, they will prove that Galileo works as designed, from the spacecraft in the sky to all the control and management operations on the ground.

"This phase is called in-orbit validation - IOV," said Javier Benedicto, the Galileo project manager at the European Space Agency (Esa), the EC's technical agent on the project.

"The intention is to test and verify the various system functionalities and the ultimate system performance," he told BBC News.

Deployment of the full Galileo system is likely to take most of the decade.

1. A large antenna will transmit signals to users on the ground
2. Distress signals are picked up by a search and rescue antenna
3. Another antenna receives information on the status of Galileo
4. The spacecraft is controlled from the ground via telecommands
5. Sensors make sure the satellite is always pointing at Earth
6. Further sensors keep an eye on where the Sun is in the sky
7. A laser retroreflector can determine the satellite's exact height
8. Radiators expel excess heat to protect electronics from overheating

Jonathan.Amos-INTERNET@bbc.co.uk

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